/*
 * feature_matching_opencv_example.cpp
 *
 *  Created on: Mar 23, 2013
 *      Author: lcad
 */
#include <stdio.h>
#include <iostream>
#include "opencv2/core/core.hpp"
#include "opencv2/features2d/features2d.hpp"
#include "opencv2/highgui/highgui.hpp"

using namespace cv;

void readme();

/** @function main */
int main( int argc, char** argv )
{
	if( argc != 3 )
	{ readme(); return -1; }

	Mat img1 = imread( argv[1], CV_LOAD_IMAGE_GRAYSCALE );
	Mat img2 = imread( argv[2], CV_LOAD_IMAGE_GRAYSCALE );

	if(!img1.data || !img2.data)
	{ std::cout<< " --(!) Error reading images " << std::endl; return -1; }

	// detecting keypoints
	SurfFeatureDetector detector(400);
	vector<KeyPoint> keypoints1, keypoints2;
	detector.detect(img1, keypoints1);
	detector.detect(img2, keypoints2);

	// computing descriptors
	SurfDescriptorExtractor extractor;
	Mat descriptors1, descriptors2;
	extractor.compute(img1, keypoints1, descriptors1);
	extractor.compute(img2, keypoints2, descriptors2);

	// matching descriptors
	BruteForceMatcher<cv::L2<float> > matcher;
	vector<DMatch> matches;
	matcher.match(descriptors1, descriptors2, matches);

	//-- Draw only "good" matches (i.e. whose distance is less than 2*min_dist )
	//-- PS.- radiusMatch can also be used here.
	std::vector< DMatch > good_matches;

	for( int i = 0; i < matches.size(); i++ )
	{ if( matches[i].distance < 0.25 )
	{ good_matches.push_back( matches[i]); }
	}

	// drawing the results
	namedWindow("matches", 1);
	Mat img_matches;
	drawMatches(img1, keypoints1, img2, keypoints2, good_matches, img_matches);
	imshow("matches", img_matches);
	waitKey(0);

	return 0;
}

/** @function readme */
void readme()
{ std::cout << " Usage: ./SURF_FlannMatcher <img1> <img2>" << std::endl; }



